Abstracts of Bell System Technical Papers Not Appearing in this Journal (01 October 1928)

Strength-Tests of Telephone Materials.J . R. TOWNSEND. Static tests, such as the ordinary tension or torsion tests, have fallen somewhat into disrepute during the last ten years, the author claims, as the ultimate strengths obtained from them are not always indicative of the forces materials will withstand in actual service. Their place is being taken by repeated-stress tests in which the sample is subjected to conditions more nearly representing those met in ordinary service. In illustration the author mentions several tests of this class being applied in Bell Telephone Laboratories on cable sheath material and springs. 

The Reduction of Atmospheric Disturbances.3 JOHN R. CARSON. In the decade or so during which the problem of eliminating or at least reducing atmospheric disturbances has been given serious and systematic study we have learned, more or less definitely, what we can and cannot do in this direction. For example, we know that there are definite limits to what can be accomplished by frequency selection. We know that directional selectivity is of substantial value, particularly when the predominant interference comes from a direction other than that of the desired signal, and we can calculate pretty well the gain to be expected from a given design. 

The object of this note is to analyze another arrangement which provides for high-frequency selection plus low-frequency balancing after detection. The broad idea of balancing out the interference is old, but no general analysis of the arrangement seems to have been made.